JPH07252402A - Aqueous epoxy resin composition - Google Patents

Abstract

PURPOSE:To provide a composition comprising an epoxy resin and an aqueous dispersion containing a cationic surfactant, extremely stable in storage stability even when stored together with a polyamine-based curing agent for a long period of time, and giving coating films good in solvent resistance and adhesivity. CONSTITUTION:The composition comprises (A) an epoxy resin and (B) an aqueous dispersion containing a cationic surfactant. The composition may further contain (C) a polyamine-based curing agent. The component (B) has quaternary ammonium salt groups as hydrophilic groups and a number-average mol.wt. of 500-100000 and contains 0.1-30wt.% of aromatic rings and 50-99.5wt.% of oxyalkylene groups. The component (A) is an epoxy resin of bisphenol type or novolak type. The solid content ratio of the components (A) and (B) as the aqueous dispersion to the component (C) is 45/55 to 90/10 by weight.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a room temperature crosslinkable aqueous epoxy resin composition which stably contains an epoxy group in a water-dispersed state for a long period of time even in the presence of a polyamine type curing agent.

[0002]

BACKGROUND OF THE INVENTION Aqueous epoxy resin compositions containing epoxy resins are widely used in the fields of adhesives, paints, fiber treatment agents and the like. Among them, physical properties such as water resistance are improved and room temperature crosslinking is carried out. Aqueous epoxy resin compositions that can be used have been studied. Examples of the water-based epoxy resin composition containing an epoxy resin and a polyamine-based curing agent include, for example, JP-B-51-44538 and JP-B-56-2.
The compositions described in Japanese Patent Publication No. 9897 and Japanese Patent Publication No. 57-10131 are proposed.

[0003]

However, in any of the above cases, the pot life is several hours to 1 in the state of an aqueous epoxy resin composition containing an epoxy resin and a polyamine-based curing agent.
It was a day, and its use was limited because it had to be added each time it was used.

[0004]

In order to solve the above-mentioned problems, the present inventors have made it possible for the epoxy group, which is a reactive group of an epoxy resin, to be stable in a water-dispersed state for a long period of time even in the presence of a polyamine-based curing agent. The present invention has been achieved as a result of intensive studies to obtain an existing room temperature crosslinkable aqueous epoxy resin. That is, the present invention provides an aqueous epoxy resin composition comprising an aqueous dispersion (A) containing an epoxy resin (a1) and a cationic surfactant (a2); an epoxy resin (a1) and a cationic surfactant (a2). ) And an aqueous dispersion (A) containing
And an aqueous dispersion (A) containing an epoxy resin (a1) and a cationic surfactant (a2), which is a room temperature crosslinkable aqueous epoxy resin composition obtained by combining a polyamine-based curing agent and a polyamine-based curing agent (B). A one-part room temperature cross-linking type aqueous epoxy resin composition comprising a polyamine-based curing agent (B).

The epoxy resin (a1) constituting (A) in the present invention includes, for example, bisphenol type (bisphenol A type, bisphenol F type, bisphenol AD type, etc.); novolak type (phenol novolac type, cresol novolak type); Cycloaliphatic compounds (alicyclic diepoxy adipate, etc.); Glycidyl ester compounds (diglycidyl phthalate, glycidyl acrylate, etc.); Glycidyl amine compounds (tetraglycidyl aminodiphenylmethane, triglycidyl aminophenol, etc.); Heterocyclic compounds (glycidyl glycol oxide) Alkylhydantoin, etc.); and mixtures of two or more thereof. Epoxy equivalent is usually 170 to 5,000
It is 0. Among these, preferred are those having high hydrophobicity, and particularly preferred are the bisphenol type and novolak type.

As the cationic surfactant (a2) constituting (A) in the present invention, the cationic surfactant (a2) having a structure of a hydrophilic group is 4
It can be classified into a primary ammonium salt type, an amine salt type, a tertiary amine type and the like, and any one can be used. The quaternary ammonium salt type can be produced by reacting a tertiary amine with an alkylating agent such as an alkyl halide or an alkyl sulfuric acid, and examples thereof include lauryl trimethyl ammonium chloride, lauryl dimethyl benzyl chloride, cetyl pyridinium bromide and stearamidoethyl diethyl methyl ammonium. Examples include methosulfate. The amine salt type can be produced by neutralizing primary to tertiary amines with an acid, and examples thereof include laurylamine acetate, triethanolamine monostearate formate, and stearamidoethyldiethylamine acetate. Examples of the tertiary amine type include 2-heptadecenyl-hydroxyethyl imidazoline and dihydroxyethyl stearyl amine. Of these, the structure of the hydrophilic group is preferably a quaternary ammonium salt type, which has good epoxy group stability when mixed with an epoxy resin.

The hydrophobic portion of the cationic surfactant (a2) contains an aromatic ring having a good affinity for the epoxy resin structure, and has a suitable amount between the aromatic ring and the cation portion which is a hydrophilic group. It is preferable to contain a polyoxyalkylene chain having a hydrophilic / hydrophobic balance. The content of aromatic ring is
It is usually 0.1 to 30% by weight, preferably 0.2 to 10% by weight. The content of the polyoxyalkylene chain is usually 50 to 99.5% by weight, preferably 60 to 98% by weight. In any case, if it exceeds this range, the aqueous dispersion of the epoxy resin becomes unstable. The cationic surfactant (a2) preferably has a molecular weight of 500 to 100,000 in order to make the epoxy resin (a1) a stable aqueous dispersion. More preferably, it is 1,000 to 50,000.
When it is less than 500, the stability of the water dispersion is poor, and when it exceeds 100,000, the viscosity of the cationic surfactant is remarkably high, and the handling at the time of producing the water dispersion becomes complicated.

The cationic surfactant having the above-mentioned preferred structure is a method of binding a quaternary ammonium salt-containing compound to an aromatic ring-containing compound obtained by adding an alkylene oxide to a phenol, and adding an alkylene oxide to the quaternary ammonium salt-containing compound. Is added to the aromatic ring-containing compound to bond with the phenols, or the aromatic ring-containing compound obtained by adding an alkylene oxide to the phenols is bonded to an alkanolamine, and then the tertiary amine is quaternized. , Can be easily synthesized. The bond between the aromatic ring-containing compound and the quaternary ammonium salt-containing compound is
For example, one compound is a glycidyl ether terminal with epichlorohydrin or the like, a hydroxyl group of the other compound, a carboxyl group, a method of reacting with an amino group, one compound with a diisocyanate compound, the isocyanate group terminal, the hydroxyl group of the other compound, Carboxyl group,
Method of reacting with amino group, hydroxyl groups of both compounds,
Examples include a method in which an alkali metal alcoholate is converted to an alkali metal compound with an alkali metal compound and an ether bond is used to connect the two with a dihalogen compound. Further, these cationic activators (a2) can be partially used in combination with nonionic activators, anionic activators and amphoteric activators.

As the polyamine-based curing agent (B), known ones can be used. For example, polyaminoamide-based curing agent [a condensate of a fatty acid polymer (dimer acid) derived from vegetable oil and polyalkylene polyamine and its modified product] ] Modified aliphatic polyamine curing agent [Modified aliphatic polyamine by reaction such as adduct of epoxy compound, Michael addition of unsaturated compound, reaction with methylol compound (Mannich reaction), reaction with ketone compound (ketiminization), etc.] Aromatic amines; and mixtures of two or more of these. Of these, preferred is that the reaction with the epoxy group proceeds at room temperature. The active hydrogen equivalent of these polyamine curing agents is usually 15 to 450 equivalents / g, preferably 20 to 20.
It is 0 equivalent / g. If the active hydrogen equivalent is less than 15 equivalents / g, the water resistance and storage stability of the resulting resin deteriorate, and
If it exceeds 50 equivalents / g, the crosslinking reaction is slow and the cured physical properties are insufficient.

The method for producing (A) is not particularly limited, but, for example, a method of premixing (a1) and (a2) and dropping and dispersing water therein, and (a1) into (a)
A method of dropping and dispersing water containing 2), a method of dropping and dispersing (a1) into water containing (a2),
1), (a2) and water may be collectively mixed and dispersed. Among these methods, in order to obtain a stable aqueous dispersion, the cationic activator (a2) is the epoxy resin (a2).
It is preferable that the method 1) easily transfer to the interface between water and water.

The aqueous epoxy resin composition of the present invention is a colloidal or emulsion type aqueous dispersion, and the epoxy group is stably retained for a long period of time. That is, in the state of being dispersed in water, the epoxy group in the epoxy resin, which is a curing reaction functional group, and the amino group in the polyamine-based curing agent are blocked and are stably retained in the micelle, but when formed into a coating film, water is removed. The micelles are volatilized and destroyed, and the epoxy group and the amino group react with each other to crosslink.

The solid content weight ratio (A) / (B) of (A) and (B) in the present invention is usually 45/55 to 90/10,
It is preferably 50/50 to 85/15. If the ratio of (A) and (B) is out of this range, sufficient crosslinking cannot be obtained and the physical properties of the cured product will be insufficient.

The aqueous dispersion of the epoxy resin obtained by the present invention can be used as it is as a conventional two-component mixed type base epoxy resin, and the epoxy group is stable for a long period of time even in the presence of a polyamine-based curing agent. Since it is retained, it can be used as a one-part room temperature crosslinking type aqueous epoxy resin composition in which a room temperature curing type polyamine-based curing agent is premixed.

The mixing method of (A) and (B) is not particularly limited, and for example, an aqueous dispersion containing (A) and (B) are mixed by a usual stirring or mixing device (paint conditioner, ball mill, kneader). , A sand grinder, a flat stone mill, etc.).

If necessary, an aqueous resin containing no epoxy-reactive active hydrogen other than (B) may be added to the aqueous epoxy resin composition of the present invention. Further, additives which are usually added for coating, adhesion or fiber treatment may be optionally added. Specific examples of the additive include a pigment, an ultraviolet absorber, an antioxidant, a heat resistance improver, a leveling agent, a film-forming auxiliary, an anti-sagging agent, a matting agent, and a curing accelerator when used as a paint. When it is used as an adhesive, an adhesiveness-imparting agent, a thickener, etc. are used, and when it is used as a fiber treatment agent, a softening agent, an antistatic agent, a flame retardant, etc.

When the composition of the present invention is used as a coating agent, its coating method may be brush coating, iron coating, roll coating, spray coating, flow coating, dipping or the like. If dried, crosslinking proceeds and the coating film hardens. If necessary, 40-100
It can also be heated to about 0 ° C to promote crosslinking.

[0017]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. In the following, "part" means part by weight and "%" means% by weight.

The abbreviations of the raw materials used in the production examples, examples and comparative examples have the following meanings.

Raw materials used Epoxy resin E-1: Epicoat 828 [made by Yuka Shell Epoxy Co., Ltd.], epoxy equivalent = 190 E-2: Epicoat 1001 [made by Yuka Shell Epoxy Co., Ltd.], epoxy equivalent = 470

Nonionic Surfactant N-1: Nonipol-500 [manufactured by Sanyo Chemical Industry Co., Ltd., poly (50 mol) ethylene oxide nonylphenyl ether] N-2: Ionet T-60C [manufactured by Sanyo Chemical Industry Co., Ltd., poly Oxyethylene sorbitan monostearate]

Polyamine curing agent A-1: React CA-101 [manufactured by Sanyo Kasei Co., Ltd., modified amine curing agent, amine value = 430, active hydrogen equivalent = 74 equivalents / g] A-2: Polymide L-45 -3 [Sanyo Chemical Co., Ltd., polyamide-based curing agent, amine value = 325, active hydrogen equivalent = 105 equivalents / g] A-3: Polyamide L-4051 [Sanyo Chemical Co., Ltd., polyamide-based curing agent, Amine value = 345, active hydrogen equivalent = 105 equivalent / g]

Production Example 1 (Production of Cationic Surfactant) Diethylethanolamine (117 g, 1 mol) was mixed with 2,320 g (40%) of propylene oxide in the presence of a potassium hydroxide catalyst.
Mol), then 4,400 g (100
Bisphenol A diglycidyl ether (Epicoat 828: manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent = 190) (190 g (0.5 mol)) was added to the precursor of the cationic surfactant (C1). −
A) was obtained. The number average molecular weight of (C1-A) by GPC (the same applies to gel permeation chromatography) was 6,650 (the same applies to polystyrene conversion), and the amine value was 16.6 mgKOH / g. In a closed container (C
1,000 g (0.15 mol) of 1-A) was taken, and 10 g (0.2 mol) of methyl chloride was added under pressure to make the terminal amino group a quaternary salt. The volatile components are distilled off under reduced pressure,
A cationic surfactant (C-1) was obtained. The amine value of the obtained cationic activator (C-1) was 5.2 mgKO.
H / g, about 70% of the terminal amino group of (C1-A)
Was quaternary chloride.

Production Example 2 (Production of Cationic Surfactant) To 228 g (1 mol) of bisphenol A, 580 g (10 mol) of propylene oxide and then 2,200 g (50 mol) of ethylene oxide were added in the presence of a potassium hydroxide catalyst, and then epichlorohydrin was added. 370 g (4 mol) and 224.4 g (4 mol) of caustic potash were reacted at 60 ° C. 8
After reacting for a period of time, the mixture was diluted with 1,000 g of toluene and excess caustic potash and potassium chloride formed were removed by filtration, and then the volatile components of the filtrate were removed under reduced pressure to give a polyoxyethylene poly-terminated glycidyl ether group. Oxypropylene bisphenol A (C2-G) was obtained. (C2-
The epoxy equivalent of G) was 1,360. Then, to 2,000 g (0.8 mol) of (C2-G), 107 g (1.2 mol) of dimethylethanolamine was added, and 80
The precursor (C2-A) of the cationic surfactant was obtained by reacting at 8 ° C for 8 hours. (C2-A) GPC
Has a number average molecular weight of 2,930 and an amine value of 3
It was 2.0 mg KOH / g. (C2-A) 1,00
0 g (0.33 mol), 60 g of methyl chloride
(0.67 mol) was added under pressure to make the terminal amino group a quaternary salt. The volatile components were distilled off under reduced pressure to obtain a cationic surfactant (C-2). The amine value of the obtained cationic activator (C-2) was 0 mgKOH / g, and it was completely quaternized.

Production Example 3 (Production of Cationic Surfactant) Nonipol-400 [manufactured by Sanyo Chemical Industry Co., Ltd., poly (40 mol) ethylene oxide nonylphenyl ether] 2,000 g (1.0 mol) was added to tolylene diisocyanate. (TDI-80: manufactured by Nippon Polyurethane Industry Co., Ltd., NCO% = 48.2) 174 g (1.0 mol) was added, and the reaction was carried out at 70 ° C. for 12 hours under a nitrogen stream to obtain an isocyanate having NCO% = 1.89. A terminal polyethylene oxide nonylphenyl ether (C3-I) was obtained. 1,000 g (0.5 mol) of (C3-I) was placed in a closed container, 44 g (0.5 mol) of dimethylethanolamine was added, and the mixture was reacted at 70 ° C. for 8 hours to prepare a cationic surfactant precursor (C3). -A) was obtained. G of (C3-A)
The number average molecular weight by PC was 2,050. Subsequently, 63 g (0.5 mol) of benzyl chloride was added under pressure to make the terminal amino group a quaternary salt. The volatile components were distilled off under reduced pressure to obtain a cationic surfactant (C-3).

Production Examples 4 to 8 (Production of Epoxy Resin Aqueous Dispersion) Epoxy resin shown in Table 1, nonionic activator, Production Example 1
To 3 by using the cationic activator and water, the epoxy resin water dispersion (epoxy EM) F-1 to F by the following operation.
-5 was obtained. 100 g of epoxy resin was placed in a 300 ml beaker and heated to 60 ° C., then 10 parts of the activator shown in Table 1 was added.
100 g of an aqueous activator solution containing 100% by weight was charged, and a fixed rotor disperser [Ultra Disperser LK-22 type manufactured by YAMATO] was used at 1350 at 30 ° C.
Dispersed for 5 minutes at 0 RPM.

[0026]

[Table 1]

Production Examples 9 to 11 (Production of Aqueous Dispersion of Polyamine Curing Agent) 100 g of the polyamine curing agent of A-1 to A-3 was added to 300 m.
It was put in a 1-liter beaker and heated to 60 ° C, then 100 g of water was added, and the rotor fixed disperser [Ultra Disperser L
K-22 type (manufactured by YAMATO Co., Ltd.) was used and dispersed at 13500 RPM for 5 minutes at 30 ° C. to obtain polyamine curing agent aqueous dispersions (amine EM) B-1 to B-3.

Examples 1 to 5 and Comparative Examples 1 to 2 F-1 to F-5 and B-1 to B-3 were mixed in a combination shown in Table 2 at room temperature to prepare a one-part room temperature crosslinkable aqueous solution. An epoxy resin composition was prepared.

Stability Test Method The epoxy EM / amine EM mixed solutions of Examples and Comparative Examples were allowed to stand at room temperature for 1 day, 10 days, and 30 days, and the epoxy group retention was measured. The epoxy group was quantified by a known method (JISK7236). The results are shown in Table 2.
Shown in.

[0030]

[Table 2]

Test Method for Cold-Crosslinked Coating Film Immediately after mixing, the epoxy EM / amine EM mixed liquids of Examples and Comparative Examples were coated on an iron plate with a thickness of about 35 micrometers and dried and cured at room temperature for 7 days. The obtained coating film was subjected to pencil hardness, cross-cut test, water resistance and acid resistance test. The results are shown in Table 3. Cross-cut test: JISK5400 Water resistance: Immersed in distilled water at room temperature for 30 days. Acid resistance: Immersed in a 5% sulfuric acid aqueous solution at room temperature for 7 days.

[0032]

[Table 3]

[0033]

The aqueous epoxy resin composition of the present invention has the following effects as compared with the conventional ones. (1) It has very good long-term storage stability in a one-component water dispersion state in which it contains a free epoxy group and is mixed with an amine curing agent. (2) In the one-liquid aqueous dispersion mixed with the amine-based curing agent, the epoxy group and the amino group react with each other due to the evaporation of water, and the crosslinking proceeds by heating at room temperature or low temperature to cure. (3) The cured film exhibits excellent physical properties such as solvent resistance, flexibility and acid resistance comparable to those of conventional solvent systems. (4) Good adhesion to various inorganic / organic substrates. Since the above-described effects are exhibited, the aqueous resin composition of the present invention is used for various coating agents [building materials (glass, slate, ceramics-based inorganics, metals such as aluminum, wood materials, plastics, etc.) interior and exterior coatings, vehicles (medium Coating, undercoat electrodeposition, chipping resistance, etc.), coatings for vehicle parts, plastics coatings for home appliances and automobile parts, anticorrosion coatings, hard coating agents, coating agents for cans, coating agents for PVC sheets, coatings for paper Agent, coating primer, etc.], adhesive (for plywood, for laminating interior material sheets, for lamination,
It is extremely useful as an industrial material such as a plastic film primer) and a fiber treatment agent (nonwoven fabric binder, waterproof treatment agent, etc.).

Claims (7)

[Claims] 1. An aqueous epoxy resin composition comprising an aqueous dispersion (A) containing an epoxy resin (a1) and a cationic surfactant (a2). 2. A room temperature crosslinkable aqueous epoxy resin composition obtained by combining an aqueous dispersion (A) containing an epoxy resin (a1) and a cationic surfactant (a2) and a polyamine-based curing agent (B). object. 3. A one-part cold crosslinking aqueous epoxy resin comprising an aqueous dispersion (A) containing an epoxy resin (a1) and a cationic surfactant (a2) and a polyamine-based curing agent (B). Composition. 4. The cationic surfactant (a2) is a fourth surfactant.
Graded ammonium salt as a hydrophilic group, and the number average molecular weight,
It is 500-100,000, The water-based epoxy resin composition in any one of Claims 1-3. 5. The cationic surfactant (a2) contains an aromatic ring in an amount of 0.1 to 30% by weight and an oxyalkylene group in an amount of 50 to 50%.
The aqueous epoxy resin composition according to any one of claims 1 to 4, containing 99.5% by weight. 6. The aqueous epoxy resin composition according to claim 1, wherein the epoxy resin (a1) is a bisphenol type epoxy resin and / or a novolac type epoxy resin. 7. A solid content weight ratio of (A) and (B) (A) /
(B) is 45 / 55-90 / 10.
The aqueous epoxy resin composition according to any one of 1.